hal_mmd: remove support for dynamically loading custom non-MMD libraries

When a dynamically loaded MMD library did not export the MMD API,
tested by the absense of aocl_mmd_get_offline_info(), the runtime
would reload the library into the global lookup scope, with the
intention of providing the symbols to another, actual MMD library.

Since this feature was never documented or used in a reference BSP,
it should be safe to remove and avoid polluting the global scope.
As an alternative, an MMD library requiring additional symbols could
dynamically link with the corresponding shared library at build time.

Signed-off-by: Peter Colberg <[email protected]>

Author: pcolberg

src/acl_hal_mmd.cpp

@@ -397,13 +397,6 @@ void *my_dlopen(const char *library_name, char **error_msg) {
   return my_dlopen_flags(library_name, RTLD_NOW, error_msg);
 #endif
 }
-void *my_dlopen_global(const char *library_name, char **error_msg) {
-#ifdef _WIN32
-  return my_dlopen_flags(library_name, 0, error_msg);
-#else
-  return my_dlopen_flags(library_name, RTLD_NOW | RTLD_GLOBAL, error_msg);
-#endif
-}
 
 void *my_dlsym(void *library, const char *function_name, char **error_msg) {
   void *symbol;
@@ -578,39 +571,17 @@ cl_bool l_load_single_board_library(const char *library_name,
     return CL_FALSE;
   }
 
-  auto *test_symbol =
-      my_dlsym(mmd_library, "aocl_mmd_get_offline_info", &error_msg);
-  if (!test_symbol) {
-    // On Linux, for custom libraries close the library (which was opened
-    // locally) and then reopen globally. For Windows, there is no option (i.e.
-    // it is always global)
-#ifdef __linux__
-    my_dlclose(mmd_library);
-    ACL_HAL_DEBUG_MSG_VERBOSE(
-        1, "This library is a custom library. Opening globally.\n");
-    mmd_library = my_dlopen_global(library_name, &error_msg);
-    if (!mmd_library) {
-      std::cout << "Error: Could not load custom library " << library_name;
-      if (error_msg && error_msg[0] != '\0') {
-        std::cout << " (error_msg: " << error_msg << ")";
-      }
-      std::cout << "\n";
-      return CL_FALSE;
-    }
-#endif
-  } else {
-    if (load_libraries) {
-      auto result =
-          l_load_board_functions(&(internal_mmd_dispatch[num_boards_found]),
-                                 library_name, mmd_library, error_msg);
-      if (result == CL_FALSE) {
-        std::cout << "Error: Could not load board library " << library_name
-                  << " due to failure to load symbols\n";
-        return result;
-      }
+  if (load_libraries) {
+    auto result =
+        l_load_board_functions(&(internal_mmd_dispatch[num_boards_found]),
+                               library_name, mmd_library, error_msg);
+    if (result == CL_FALSE) {
+      std::cout << "Error: Could not load board library " << library_name
+                << " due to failure to load symbols\n";
+      return result;
     }
-    ++num_boards_found;
   }
+  ++num_boards_found;
 
   return CL_TRUE;
 }